Evaluation of the Efficacy of Methyl Bromide in the Decontamination of Building and Interior Materials Contaminated with Bacillus anthracis Spores

• Joseph P. Wood ^[1] ; Morgan Wendling ^[2] ; William Richter ^[2] ; Andrew Lastivka ^[2] ; Leroy Mickelsen ^[1]
  1. [1] Environmental Protection Agency

     Environmental Protection Agency

     Estados Unidos

     
  2. [2] Otho S. A. Sprague Memorial Institute

     Otho S. A. Sprague Memorial Institute

     City of Chicago, Estados Unidos

     
• Localización: Applied and Environmental Microbiology, ISSN 0099-2240, Vol. 82, Nº 7, 2016, págs. 2003-2011
• Idioma: inglés
• Enlaces
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• Resumen

  • The primary goal of this study was to determine the conditions required for the effective inactivation of Bacillus anthracis spores on materials by using methyl bromide (MeBr) gas. Another objective was to obtain comparative decontamination efficacy data with three avirulent microorganisms to assess their potential for use as surrogates for B. anthracis Ames. Decontamination tests were conducted with spores of B. anthracis Ames and Geobacillus stearothermophilus, B. anthracis NNR1Δ1, and B. anthracis Sterne inoculated onto six different materials. Experimental variables included temperature, relative humidity (RH), MeBr concentration, and contact time. MeBr was found to be an effective decontaminant under a number of conditions. This study highlights the important role that RH has when fumigation is performed with MeBr. There were no tests in which a ≥6-log10 reduction (LR) of B. anthracis Ames was achieved on all materials when fumigation was done at 45% RH. At 75% RH, an increase in the temperature, the MeBr concentration, or contact time generally improved the efficacy of fumigation with MeBr. This study provides new information for the effective use of MeBr at temperatures and RH levels lower than those that have been recommended previously. The study also provides data to assist with the selection of an avirulent surrogate for B. anthracis Ames spores when additional tests with MeBr are conducted.